In this paper, two experiments were conducted to clarify the influence of coating amount of polymer cement paste on uniformity of thickness after hardening, adhesiveness, and watertightness. The followings are concluded from the test results. Uniformity of thickness after hardening is improved on vertical parts with a smaller coating amount. For Adhesiveness, a large coating amount on vertical parts is likely to cause adhesion defects. Regarding watertightness, a large coating amount is likely to cause moisture movement at the interface between hardened paste and waterproofing sheet above it. They are improved by reducing the coating amount of polymer cement paste.
Nowadays, structural design of buildings considers large earthquakes such as long-period long-duration ground motions. Generally, design criteria are not enlarged as increasing intensities of input ground motions. Practical and theoretical limitations to control seismic responses are unknown. Expected seismic responses of structures and required aseismic performances for the structures under an earthquake can be drawn as a demand spectrum. This paper presents a normalized demand spectrum to investigate sinusoidal responses of SDOF systems. Pareto front of the demand spectra considering a trade-off between displacement response and acceleration response is also presented.
In this paper, we assume that furniture such as a tall shelve is a rigid body allowing the shift of gravity center location, and focus on rocking vibration in buildings considering collision with the wall during earthquakes. To represent building response characteristics, we propose a new double impulse method, defined as VADI (Varied Amplitude Double Impulse), where the magnitudes of the two impulses are independent of each other. Various timing of second impulse acting to rigid body in VADI are considered, and in each case the overturning limit on critical combination of impulse amplitudes is derived in closed-form.
Aiming for accurate evaluation of bearing capacity and settlement behavior of multi-belled cast-in-place piles in sand, the characteristics of load-settlement relations and the effect of bell spacing on bearing capacity were investigated by experimental techniques. The findings are summarized as follows: 1) The average curves of the load-settlement relations of intermediate bells based on six full-scale load tests showed larger initial stiffness and curvature than the recommended curve for a pile tip by AIJ. 2) The results of centrifuge modelling tests indicated that smaller bell spacing brought lower resistance of an intermediate bell and the change of ground failure mechanism.
This paper aims to evaluate the seismic performance of wooden houses which have sliding-base structure as a seismic isolation system. The sliding base consists of a reinforced concrete (RC) slab, an RC foundation, and sliding materials. First, full-scale shaking table tests on two-story wooden frames with / without the sliding base were carried out. Then, two-dimensional frame models were developed, and time-history response analysis were conducted to simulate the test results. It is found that the sliding base is effective to reduce the seismic response of the wooden frame and the numerical model simulates the dynamic behavior accurately.
In a design of large or high-rise timber construction in urban area, fireproof covering often becomes a problem from economic and aesthetic point of view. As a solution, several hybrid structural systems have been developed that combine a fireproof steel framework and timber seismic members without fireproof covering.
In our proposal, steel column and CLT beam are semi-rigidly jointed by C-shaped slotted steel plate and steel dowels. This paper describes the performance of this moment resisting joint from the viewpoint of elasto-plastic behavior and stress distribution, basing on the structural tests, theorical calculations and numerical analyses.
A hysteresis restoring force characteristic model and a method for calculating the equivalent viscous damping ratio of a beam with two rotational springs at both the outer end of the general and widened beam end were proposed. A damage evaluation method applying the member model was proposed, and the reduction in rigidity according to the degree of damage was reflected in the hysteresis restoring force characteristic model of reused members. The dismantled specimens were assembled again and re-tested to confirm the consistency between the model and the results.
This paper deal with box column built-up by partial penetration welding at the corners. The objective is to propose the evaluation method of full plastic strength of beam-column joint panel of box column built-up by partial penetration welding which is considered about the influences of loading direction, aspect ratio, axial force and welding penetration depth of corner seams. Firstly, from loading test and finite element method analysis, we evaluate the structural performance of panel zone and the influences of above parameters on full plastic strength. From the results, we propose the evaluation method of full plastic strength.
The ultimate flexural strength of concrete-filled steel tubular (CFT) columns is improved by using high-strength materials. The current design formula of CFT columns excludes high strength materials. CFT columns that used in buildings are generally subjected to bending and shear force, but this formula was verified by uniform bending tests. In this paper, it was attempted to formulate the ultimate flexural strength and limit displacement of CFT columns by organizing previous experiments that CFT columns were subjected to bending and shear force.
This study aimed to investigate the influence of rotational resistance of dowel-type timber connections on the fire performance of timber frames. Eight large-scale tests were conducted under both ambient and fire conditions using simply supported timber beams and timber frames with dowel-type connections. The failure times of the frames were extended compared to those of the simply supported beams, as the rotational resistance of dowel-type connections reduced the bending moment of the connected beam. The influence of the rotational resistance was especially significant during the cooling down phase after a fire, extending the failure time by more than 60 minutes.
An evaluation method of hydroelastic response and structural failure of pontoon type floating offshore wind turbines for wind and ocean waves is presented. The response to the mean wind speed is analyzed statically and to both variable wind speed and waves are analyzed by using a stationary random vibration theory. The failure is evaluated by using a first order reliability method. A boundary and finite element hybrid model is used to the hydroelastic analysis of the structures. Moreover, variations of the response and the failure probability of the structures for different wind speed and direction are discussed.